Pavement

The Everyday Miracle

You'll never ignore that ordinary strip of pavement under your wheels again

lisa margonelli

Harvey, a passionate professor of civil and environmental engineering, gets all torn up by damaged pavement. (C.J. Burton)

"If asphalt doesn't get traffic it falls apart," says Norm. "The cars knead the pavement and keep it alive."

The Lincoln Highway's sketchy condition was directly responsible for the creation of the interstate highway system 35 years later. At the end of World War I, the U.S. Army sent a truck convoy—led by a young, bored officer named Dwight D. Eisenhower—across the highway. It took the convoy two months, traveling at an average speed of 6 mph, breaking bridges, getting stuck in the mud and crunching through fragile roads. In 1956, President Eisenhower paved the country with the Interstate Highway Act.

Norm and Lloyd take me to a rough toll road constructed for gold miners in 1852, so steep that travelers had to disassemble their wagons and pull them over the ridge piece by piece. We pay a call to a beautifully graded road built by an engineer named Olgivie in 1861, which still runs nearly intact through the Sierras. Near sunset we drop in on a macadam stretch of the Lincoln Highway, built in 1912 through marshy land and under trees. Twelve feet wide and only a few inches thick, it looks as fragile as a potato chip.

"Imagine," Lloyd says, "Eisenhower rode over this. Right over this. With that military convoy, they could have torn this all up."

The small rocks that make up the surface of the road shine slightly in the low sun. "I highly suspect this was sprayed with asphalt," says Norm, as he checks the work orders for confirmation. "It hasn't been fixed since 1944."

A concrete road, they surmise, would have long ago cracked on this soft marsh ground, while asphalt could drape on the land like a heavy blanket. We are standing in the road like a bunch of Encyclopedia Browns waiting for a eureka moment when Norm, having given up on finding anything useful in the work order, shouts, "Look! You can see the nozzles."

You can, but in reverse. Where the nozzles drizzled asphalt on the road, the surface is ridged, and in places the spray missed, the rocks have all blown away. I have a moment; I feel connected to those men who built our parthenons, long ago.

Chapter 5: Pavement bleeds

"It's bloody highway," snorts J.T. Harvey, professor of pavement in civil and environmental engineering at University of California at Davis. He points at something red, translucent and grisly in the middle of the lane ahead of us, and continues bearing down on it at 60 mph in his pickup truck. Just before we remurder whatever it is, he says, "You think, 'Oh my god, what happened here?' And then you realize, at this time of the year, oh yeah, it's tomato season."

We whisk over the vegetable smear. To Harvey, pavements are so animated they might as well bleed. They are tricky, willful and puzzling, ever-shifting. The only thing a road doesn't do is lie quietly on the ground. "Pavements are really complex structures, more complex than buildings or bridges," he says, "It's harder to build a pavement than to send a man to the moon."

Take the pavement we're on, State Highway 113. Built of more than a foot of concrete, standing on top of aggregate treated with asphalt, which is on top of a tomato field, it gives the impression that it's massive, and passive. To Harvey, though, it's a flat gymnast. During the day it heats up on top and forms a convex curve. At night it cools off and, because the underside is moist, forms a concave curve. Over the years, it will crack under pressure of the double-trailer trucks hauling tomatoes over it. Closer to Davis, the worst has already happened. Moisture has seeped under the joints, washed away the supporting aggregate and left tiles that flap around when we drive over them, making for a bumpy ride and the notorious wuka-wuka sound of flopping concrete. "Rough pavement can increase a truck's fuel consumption by 5 percent," says Harvey, ominously.

Harvey is a big, optimistic man in crisp hiking shorts, but he shoulders what he calls "the curse." Once a relatively carefree music major, Harvey became interested in forestry, then water, and then pavement, which delivered him to his fate. "Before you have the curse, all those cracks in the asphalt are just squiggly lines," he says. "But after you know what caused them, you don't see squiggles, you see deep problems."